/*
 * netutils: ping implementation
 */

#include "lwip/opt.h"

#include "lwip/mem.h"
#include "lwip/icmp.h"
#include "lwip/netif.h"
#include "lwip/sys.h"
#include "lwip/sockets.h"
#include "lwip/inet.h"
#include "lwip/inet_chksum.h"
#include "lwip/ip.h"

/**
 * PING_DEBUG: Enable debugging for PING.
 */
#ifndef PING_DEBUG
	#define PING_DEBUG     LWIP_DBG_ON
#endif

/** ping receive timeout - in milliseconds */
#define PING_RCV_TIMEO rt_tick_from_millisecond(2000)
/** ping delay - in milliseconds */
#define PING_DELAY     rt_tick_from_millisecond(1000)

/** ping identifier - must fit on a u16_t */
#ifndef PING_ID
	#define PING_ID        0xAFAF
#endif

/** ping additional data size to include in the packet */
#ifndef PING_DATA_SIZE
	#define PING_DATA_SIZE 32
#endif

/* ping variables */
static u16_t ping_seq_num;
struct _ip_addr {
	rt_uint8_t addr0, addr1, addr2, addr3;
};

/** Prepare a echo ICMP request */
static void ping_prepare_echo(struct icmp_echo_hdr* iecho, u16_t len)
{
	size_t i;
	size_t data_len = len - sizeof(struct icmp_echo_hdr);

	ICMPH_TYPE_SET(iecho, ICMP_ECHO);
	ICMPH_CODE_SET(iecho, 0);
	iecho->chksum = 0;
	iecho->id     = PING_ID;
	iecho->seqno  = htons(++ping_seq_num);

	/* fill the additional data buffer with some data */
	for(i = 0; i < data_len; i++) {
		((char*)iecho)[sizeof(struct icmp_echo_hdr) + i] = (char)i;
	}

	iecho->chksum = inet_chksum(iecho, len);
}

/* Ping using the socket ip */
static err_t ping_send(int s, ip_addr_t* addr, int size)
{
	int err;
	struct icmp_echo_hdr* iecho;
	struct sockaddr_in to;
	size_t ping_size = sizeof(struct icmp_echo_hdr) + size;
	LWIP_ASSERT("ping_size is too big", ping_size <= 0xffff);

	iecho = rt_malloc(ping_size);

	if(iecho == RT_NULL) {
		return ERR_MEM;
	}

	ping_prepare_echo(iecho, (u16_t)ping_size);

	to.sin_len = sizeof(to);
	to.sin_family = AF_INET;
	to.sin_addr.s_addr = addr->addr;

	err = lwip_sendto(s, iecho, ping_size, 0, (struct sockaddr*)&to, sizeof(to));
	rt_free(iecho);

	return (err == ping_size ? ERR_OK : ERR_VAL);
}

static int ping_recv(int s, int* ttl)
{
	char buf[64];
	int fromlen = sizeof(struct sockaddr_in), len;
	struct sockaddr_in from;
	struct ip_hdr* iphdr;
	struct icmp_echo_hdr* iecho;

	while((len = lwip_recvfrom(s, buf, sizeof(buf), 0, (struct sockaddr*)&from, (socklen_t*)&fromlen)) > 0) {
		if(len >= (sizeof(struct ip_hdr) + sizeof(struct icmp_echo_hdr))) {
			iphdr = (struct ip_hdr*)buf;
			iecho = (struct icmp_echo_hdr*)(buf + (IPH_HL(iphdr) * 4));

			if((iecho->id == PING_ID) && (iecho->seqno == htons(ping_seq_num))) {
				*ttl = iphdr->_ttl;
				return len;
			}
		}
	}

	return len;
}

rt_err_t ping(char* target, rt_uint32_t times, rt_size_t size)
{
	int s, ttl, recv_len;
	struct timeval timeout = { PING_RCV_TIMEO / RT_TICK_PER_SECOND, PING_RCV_TIMEO % RT_TICK_PER_SECOND };
	ip_addr_t ping_target;
	rt_uint32_t send_times;
	rt_tick_t recv_start_tick;
	struct _ip_addr {
		rt_uint8_t addr0, addr1, addr2, addr3;
	} *addr;

	send_times = 0;
	ping_seq_num = 0;

	if(size == 0)
		size = PING_DATA_SIZE;

	if(inet_aton(target, &ping_target) == 0) {
		rt_kprintf("ping: unknown host %s\n", target);
		return -RT_ERROR;
	}

	addr = (struct _ip_addr*)&ping_target;

	if((s = lwip_socket(AF_INET, SOCK_RAW, IP_PROTO_ICMP)) < 0) {
		rt_kprintf("ping: create socket failled\n");
		return -RT_ERROR;
	}

	lwip_setsockopt(s, SOL_SOCKET, SO_RCVTIMEO, &timeout, sizeof(struct timeval));

	while(1) {
		if(ping_send(s, &ping_target, size) == ERR_OK) {
			recv_start_tick = rt_tick_get();

			if((recv_len = ping_recv(s, &ttl)) >= 0) {
				rt_kprintf("%d bytes from %d.%d.%d.%d icmp_seq=%d ttl=%d time=%d ticks\n", recv_len, addr->addr0,
				           addr->addr1, addr->addr2, addr->addr3, send_times, ttl, rt_tick_get() - recv_start_tick);
			} else {
				rt_kprintf("From %d.%d.%d.%d icmp_seq=%d timeout\n", addr->addr0, addr->addr1, addr->addr2,
				           addr->addr3, send_times);
			}
		} else {
			rt_kprintf("Send %d.%d.%d.%d - error\n", addr->addr0, addr->addr1, addr->addr2, addr->addr3);
		}

		send_times ++;

		if(send_times >= times) break;  /* send ping times reached, stop */

		rt_thread_delay(PING_DELAY); /* take a delay */
	}

	lwip_close(s);

	return RT_EOK;
}
#ifdef RT_USING_FINSH
#include <finsh.h>

FINSH_FUNCTION_EXPORT(ping, ping network host);

int cmd_ping(int argc, char** argv)
{
	if(argc == 1) {
		rt_kprintf("Please input: ping <host address>\n");
	} else {
		ping(argv[1], 4, 0);
	}

	return 0;
}
FINSH_FUNCTION_EXPORT_ALIAS(cmd_ping, __cmd_ping, ping network host);
#endif
